San Diego County vector control officers reported Friday that they had found wild mice in Torrey Pines State Reserve that tested positive for hantavirus, a disease that can spread to humans and is potentially fatal.

The disease spreads when mouse feces or urine gets airborne and inhaled, so county public health officials warned residents to use a damp cleaning method on any surfaces where mice are suspected to have scurried.

A county public health specialist said Friday that of special concern are structures along the "urban-wildland interface," that is, homes with an undeveloped canyon or ridgeline nearby that have a greater chance of attracting a wild mouse, not a house mouse.

A resident of one such community, a condominium complex just east of Torrey Pines, said Friday that the news of the disease-carrying mice being captured so close to his home had him worried.

The resident, Greg McDonald, has battled mice in his condominium just west of Interstate 5 for years. McDonald said that while he hadn't seen any mice this year, previous years found the rodents began showing up around October, when temperatures began the dip. He said he took care to clean everything that mice may have touched.

A North County exterminator said Friday that hantavirus hasn't been a problem he had encountered in eight years on the job, but that the recent wildfires may cause wild animals to seek new foraging grounds.

"The fires could have displaced them and they could be coming down to homes now," said John Lawton, a field representative in the San Marcos office of Truly Nolen Inc., the pest control company whose yellow company cars are dressed up with mouse ears, whiskers and a tail.

"If they can't get any food, they could be looking to our communities," Lawton said.

Hantavirus is carried by wild rodents, primarily deer or field mice, and is left in droppings and urine that can be inhaled by humans, according to the San Diego County Department of Environmental Health. The airborne virus can cause hantavirus pulmonary syndrome, which has symptoms similar to the flu, but in rare cases it can lead to severe breathing difficulties and even death, county officials said.

The county has caught a few hantavirus-carrying mice each year, but only two humans have been known to contract the disease in San Diego County, both in 2004, and neither case proved fatal. The disease itself was only discovered in 1993, when several young adults in the "Four Corners," where New Mexico, Arizona, Colorado and Utah meet, contracted severe breathing difficulties and half of them died. The Centers for Disease Control and Prevention reports that as of March, 465 cases of hantavirus pulmonary syndrome have been reported in the United States. Of those, 35 percent have been fatal.

While hikers in Torrey Pines State Reserve should have "not a care in the world" about catching hantavirus, folks who live near wilderness ought to be careful when cleaning in enclosed spaces, said Chris Conlan, the county Department of Environmental Health's supervising vector ecologist.

"Just because you have houses all around you, you're not out of the woods, if you have a canyon nearby," Conlan said. "The odds go up the closer you are to that wildland."

Still, Conlan said there are simple things people can do to make sure they don't contract hantavirus. First and foremost, he said, is that "a broom plus mice droppings equals bad." Sweeping mouse poop stirs particles that can become airborne.

Instead, the county's Department of Environmental Health encouraged residents to:

- ventilate the affected area by opening doors and windows for at least 30 minutes;

- use rubber gloves;

- spray a 10 percent bleach solution (two tablespoons bleach to one cup of water) onto dead rodents, rodent droppings, nests, contaminated traps and surrounding areas;

- let the disinfectant stand for at least 15 minutes before cleaning;

- clean with a sponge or a mop;

- place disinfected waste into two plastic bags, seal them and discard in the trash;

- wash gloves in the bleach solution, then soap and water, and dispose of them using the same double-bag method;

- thoroughly wash your bare hands with soap and water.

More information about the disease and how to prevent it can be found at San Diego County's vector control Web site, www.sdvector.com, or by calling (858) 694-2888.

Contact staff writer Denis Devine at (760) 740-5415 or ddevine@nctimes.com.